http://www.nikkei-science.com/?p=46843

http://science.srad.jp/story/15/05/15/0558250/

http://www3.nhk.or.jp/news/html/20150516/k10010081531000.html

http://headlines.yahoo.co.jp/hl?a=20150519-00000072-jij-pol

http://headlines.yahoo.co.jp/hl?a=20150519-00050074-yom-soci